Enzymological Characterization of Secreted Proteinases from Candida parapsilosis and Candida lusitaniae
Opportunistic pathogens of the genusCandidaproduce secreted aspartic proteinases (Saps) that are considered as one of the virulence factors. While Saps ofC. albicansandC. tropicalishave been studied extensively, information concerning proteinases secreted by other pathogenicCandidaspecies is scarce. To our knowledge, enzymologic characterizations of Sap ofC. parapsilosis(Sapp1p) andC. lusitaniae(Saplp) are limited. We have purified Saps ofC. parapsilosisandC. lusitaniaefrom yeast culture supernatants and detected only one gene product of both Sapp1p and Saplp using isoelectric focusing and N-terminal sequencing. Molecular weight of Saplp determined by SDS-PAGE is approximately 42 000. For the highest enzyme activity, both Sapp1p and Saplp require pH ranging from 3 to 4 and temperature between 27-40 °C for Saplp and 45 °C for Sapp1p, respectively. At physiological temperature, both the proteinases are stable. The characterization of Saps of clinical isolates ofC. parapsilosisandC. lusitaniaeshould contribute to design of novel drugs specifically targeted on proteinases.